title: Long-term magnesium sulfate tocolysis and maternal osteoporosis in a triplet pregnancy: a case report.
abstract: Prolonged infusion of magnesium sulfate has been used for the treatment of refractory preterm labor. Long-term magnesium sulfate tocolytic therapy either alone or in combination with other tocolytic agents has been reported to be safe and effective with minimal maternal side effects. There has been only one previous report of a disturbance in maternal calcium homeostasis, which included decreased distal radius bone density and hypercalciuria as a result of prolonged magnesium sulfate infusion. This article reports the first case of bilateral fracture of the calcanei in the postpartum period secondary to osteoporosis associated with prolonged magnesium sulfate tocolysis and bed rest. A 35-year-old white female with a triplet pregnancy of 25 weeks' gestation was admitted in preterm labor. Bed rest, intravenous magnesium sulfate tocolysis, and intermittent subcutaneous terbutaline were necessary to maintain uterine quiescence for 65 days. The patient received weekly betamethasone for 6 weeks for the acceleration of fetal lung maturation. Daily prenatal multivitamins and low-dose subcutaneous heparin for thromboprophylaxis were given. Efforts at tocolysis were ultimately not successful and the patient underwent a cesarean section delivery at 34 2/7 weeks' gestation. The patient's postoperative course was complicated by osteoporosis and bilateral stress fractures of the calcanei. This case report demonstrates that stress fractures secondary to osteoporosis may be associated with prolonged magnesium sulfate therapy and bed rest in higher order multiple pregnancy. Other possible contributing factors to osteoporosis include heparin thromboprophylaxis and suboptimal calcium supplementation. Therefore, in circumstances of prolonged bed rest and magnesium sulfate tocolysis, additional daily calcium supplementation would be well advised.
authors.affiliation: Department of Obstetrics and Gynecology, Jefferson Medical College, Philadelphia, Pennsylvania, USA.
authors.forename: A L
authors.initials: AL
authors.lastname: Levav
authors.forename: L
authors.initials: L
authors.lastname: Chan
authors.forename: R J
authors.initials: RJ
authors.lastname: Wapner
mesh_terms: D000328:Adult; D000925:Anticoagulants / Q000627:therapeutic use; D001510:Bed Rest / Q000009:adverse effects; D002111:Calcaneus / Q000293:injuries / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D002585:Cesarean Section; D005260:Female; D015775:Fractures, Stress / Q000139:chemically induced / Q000209:etiology; D006493:Heparin / Q000627:therapeutic use; D006801:Humans; D007231:Infant, Newborn; D008278:Magnesium Sulfate / Q000008:administration & dosage / Q000009:adverse effects*; D008297:Male; D007752:Obstetric Labor, Premature / Q000188:drug therapy; D010024:Osteoporosis / Q000139:chemically induced / Q000150:complications / Q000209:etiology*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000139:chemically induced / Q000209:etiology*; D011256:Pregnancy Outcome; D011272:Pregnancy, Multiple; D013726:Terbutaline / Q000627:therapeutic use; D015145:Tocolysis / Q000009:adverse effects*; D015149:Tocolytic Agents / Q000008:administration & dosage / Q000009:adverse effects*; D014310:Triplets
chemical_list: D000925:Anticoagulants; D015149:Tocolytic Agents; D008278:Magnesium Sulfate; D006493:Heparin; D013726:Terbutaline; D002118:Calcium